1. Field
The following description relates generally to wireless communications, and more particularly to implementing optimizations that support uplink coordinated multi-point (CoMP) in a wireless communication environment.
2. Background
Wireless communication systems are widely deployed to provide various types of communication content such as, for example, voice, data, and so on. Typical wireless communication systems can be multiple-access systems capable of supporting communication with multiple users by sharing available system resources (e.g., bandwidth, transmit power, . . . ). Examples of such multiple-access systems can include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, orthogonal frequency division multiple access (OFDMA) systems, and the like. Additionally, the systems can conform to specifications such as third generation partnership project (3GPP), 3GPP long term evolution (LTE), ultra mobile broadband (UMB), and/or multi-carrier wireless specifications such as evolution data optimized (EV-DO), one or more revisions thereof, etc.
Generally, wireless multiple-access communication systems can simultaneously support communication for multiple mobile devices. Each mobile device can communicate with one or more base stations via transmissions on forward and reverse links. The forward link (or downlink) refers to the communication link from base stations to mobile devices, and the reverse link (or uplink) refers to the communication link from mobile devices to base stations. Further, communications between mobile devices and base stations can be established via single-input single-output (SISO) systems, multiple-input single-output (MISO) systems, multiple-input multiple-output (MIMO) systems, and so forth. In addition, mobile devices can communicate with other mobile devices (and/or base stations with other base stations) in peer-to-peer wireless network configurations.
Traditionally, in a wireless communication network with multiple base stations and multiple mobile devices, each mobile device is typically associated with a particular one of the multiple base stations. For instance, a mobile device can be associated with a given base station as a function of various factors such as signal strength, Channel Quality Indicator (CQI), and so forth. Thus, the mobile device can be served by the given base station (e.g., uplink and downlink transmissions can be exchanged there between, . . . ), while other base stations in vicinity can generate interference.
Moreover, cooperation between base stations has become more commonly leveraged. In particular, multiple base stations in a wireless communication network can be interconnected, which can allow for sharing data between base stations, communicating there between, and so forth. For instance, in a wireless communication network deployment across a city, base stations included in the deployment can serve a set of mobile devices located within proximity of the base stations. Thus, multiple sources and/or destinations can be utilized as part of a cooperation strategy for transmission and reception of data, control signaling, and/or other information between devices in the wireless communication network. Use of multiple sources and/or destinations for respective transmissions can yield higher data rates, improved signal quality, and other such benefits. According to an example, the wireless communication network can be a network multiple-input multiple-output (N-MIMO) system or a coordinated multi-point (CoMP) system, in which a plurality of base stations can cooperate to exchange information with one or more mobile devices.
In an uplink N-MIMO system or uplink CoMP system, a mobile device can transmit an uplink signal to a plurality of base stations. Conventionally, mobile devices can be scheduled to transmit respective uplink signals to the plurality of base stations on overlapping sets of resources. Accordingly, high levels of interference oftentimes result from more than one mobile device leveraging a common set of resources for sending uplink signals. Moreover, resources utilized for transmitting an acknowledgment over the downlink to a mobile device (e.g., responsive to a received uplink signal, . . . ) commonly correspond to resources assigned to the mobile device and employed for transmitting the uplink signal. Thus, conventional techniques can result in the same resources being utilized for transmitting acknowledgments over the downlink to more than one mobile device. Since uplink signals can be sent by more than one mobile device, it can be desirable to send respective acknowledgments via different resources on the downlink to the more than one mobile device.